''Eomysticetus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

baleen whale Baleen whales (), also known as whalebone whales, are marine mammals of the order (biology), parvorder Mysticeti in the infraorder Cetacea (whales, dolphins and porpoises), which use baleen plates (or "whalebone") in their mouths to sieve plankt ...

from the late

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

(

Chattian The Chattian is, in the geologic timescale, the younger of two ages or upper of two stages of the Oligocene Epoch/Series. It spans the time between . The Chattian is preceded by the Rupelian and is followed by the Aquitanian (the lowest stage ...

)

Chandler Bridge Formation The Chandler Bridge Formation is a Formation (geology), geologic formation in South Carolina. It preserves fossils dating back to the Chattian (Late Oligocene) of the Paleogene Period (geology), period, corresponding to the Arikareean in the Nort ...

South Carolina South Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders North Carolina to the north and northeast, the Atlantic Ocean to the southeast, and Georgia (U.S. state), Georg ...

. (148Mb)

Taxonomy

''Eomysticetus'' is a member of the family

Eomysticetidae Eomysticetidae is a family of extinct mysticetes belonging to Chaeomysticeti (toothless mysticetes). It is one of two families in the basal chaeomysticete clade Eomysticetoidea (the other being Cetotheriopsis, Cetotheriopsidae). Description Eo ...

, which also includes '' Micromysticetus'', '' Tohoraata'', '' Tokarahia'', and '' Yamatocetus''. There are two species of ''Eomysticetus'', ''E. whitmorei'' and ''E. carolinensis'', both from the

of South Carolina.

Physical characteristics

The skull was around in length. Like more evolved baleen whales, its jaws had

baleen Baleen is a filter feeder, filter-feeding system inside the mouths of baleen whales. To use baleen, the whale first opens its mouth underwater to take in water. The whale then pushes the water out, and animals such as krill are filtered by th ...

instead of

teeth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

, meaning that it could filter plankton with its baleen plates. However, primitive baleen whales may have retained enamel coated teeth embedded in the

gums The gums or gingiva (: gingivae) consist of the mucosal tissue that lies over the mandible and maxilla inside the mouth. Gum health and disease can have an effect on general health. Structure The gums are part of the soft tissue lining of the ...

, similar to modern

sperm whales The sperm whale or cachalot (''Physeter macrocephalus'') is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus '' Physeter'' and one of three extant species in the sperm whale super ...

. Baleen whales, as a group, may be sensitive to low-frequency sounds. Unlike modern baleen whales, ''Eomysticetus'' had a blowhole that was positioned ahead of the eyes, and the characteristics of its vertebrae and flipper bones are akin to those of

archaeocetes Archaeoceti ("ancient whales"), or Zeuglodontes in older literature, is an obsolete paraphyletic group of primitive cetaceans that lived from the Early Eocene to the late Oligocene (). Representing the earliest cetacean radiation, they include th ...

like ''

Basilosaurus ''Basilosaurus'' (meaning "king lizard") is a genus of large, predatory, prehistoric archaeocete whale from the late Eocene, approximately 41.3 to 33.9 million years ago (mya). First described in 1834, it was the first archaeocete and prehisto ...

''.

References

{{Taxonbar, from=Q15729942 Baleen whales Oligocene cetaceans Prehistoric mammals of North America Fossil taxa described in 2002 Prehistoric cetacean genera